Write voltage and read reference current generator for multi-level Ge2Sb2Te5-based phase change memories with temperature characteristics tracking

This paper gives a write voltage and read reference current generator considering temperature characteristics for multi-level Ge₂Sb₂Te₅-based phase change memories (PCMs). Since the optimum SET and RESET voltages changes by the temperature, the voltage supply circuit must track this characteristic. In addition, the measurement results show that the read current depends on not only the current but also the write temperatures. Dividing into three temperature regions and using the variable temperature coefficient current generator, the proposed generator can track both the linear write voltage and the exponential read current changes by the temperature.